Lymphangioleiomyomatosis (LAM) is a rare pulmonary disease of unknown etiology which occurs in women, primarily in their reproductive years. The first goal of this study is to establish a registry of individuals with LAM (about 200 of whom are currently known) by forming a consortium of clinical centers and referring physicians who treat LAM patients. The LAM Registry will be coordinated by a Data Coordinating Center (DCC) at The Cleveland Clinic Foundation. The cohort of identified individuals with LAM will be used to characterize the clinical features of subjects with LAM and the course of the disease. Other goals will be to examine the clinical features of LAM patients referred to lung transplantation and assess the efficacy of this therapy. Lung tissue will be collected from participants to allow future studies into the molecular -basis of LAM. The assembled cohort will permit future research in therapeutic trials. The DCC will coordinate the scientific and operational aspects of the Registry. This includes finalizing the protocol, data forms, and Manual of Operations in conjunction with the Steering Committee. An Oracle-based data management system will be developed to assure accurate collection of Registry data. The participating clinical centers and referring physicians will be instructed by the DCC on procedures to enroll LAM patients into the Registry and to collect data during an up to four-year follow up. All deaths will be reviewed by a Death Review Committee. Study progress will be reported to the Steering Committee and an External Advisory Committee based on analyses by the DCC. New statistical methodology will be developed, as needed, to properly analyze the data.